1. Technical Field
This Patent Document relates generally to sensors and sensing, such as may be used in measuring or detecting the response of a sensor to a target, for example, based on position, proximity or physical state or condition.
2. Related Art
A resonant sensor includes a resonator configured for steady-state (non-sensing) operation at a resonant frequency and amplitude. Resonant sensing is based on changes in sensor resonance_state as manifested by, for example, changes in resonator oscillation amplitude and frequency resulting from changes in sensor/resonator resonant impedance in response to a target. Sensor response to a target can be caused, for example, by proximity or position of the target relative to the sensor, or some sensed physical state of the target.
For example, in case of inductive sensing, sensor (resonator) impedance is affected by a storage or loss in magnetic flux energy output from the inductive sensing coil of an LC resonator, such as may be caused by the eddy current effect associated with a conductive target. In case of a sensor with a resonator based on a variable capacitor, resonator impedance is affected by the storage or loss of electric field energy. In case of a piezo-electric resonator, sensor resonance is affected by a change in mechanical stress on the piezo-crystal.
While this Background information is presented in the context of sensor applications, the utility of the Disclosure is not limited to such applications, but is more generally directed to a methodology for measuring changes in sensor/resonator resonant impedance in response to a target.